Are you hurting your relationship without even knowing it? Here are eight habits that researchers say can lead to marital problems.

By Jena Pincott

Photo: Thinkstock

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You Were Never the Smiley Type

You knew those stiff-faced yearbook photos would come back to haunt you one day. But this one’s unexpected: Women with “low intensity” smiles in their childhood and college photos are five times likelier to get divorced as adults than those who smiled effusively, found a 2009 study at DePauw University. A bright, wide smile represents an underlying positive disposition and worldview—undoubtedly helpful in marriage. Lifelong smilers may be the type to seek and sustain lasting relationships, and because smiling is contagious, their partners may be happier too. The good news about smiling: If you want, you can “fake it ‘til you make it.” As we know from the facial feedback theory of emotion, smiling deliberately—even if you need to put a pen between your lips to get your lips to turn that way—can make you feel happier, because facial expressions influence emotions.